The present invention relates to a pushbutton device for use on electronic apparatus such as electronic watches, electronic calculators, or the like.
As shown in FIG. 1, a conventional pushbutton device for use on various small-size electronic apparatus such as electronic watches or electronic calculators includes a pipe or tubular body 2 affixed to a casing 1 and a pushbutton body 3 spring-biased in the direction to expose its head out of the pipe 2. The pushbutton device is actuated by depressing the pushbutton head with a fingertip until the head enters completely into the pipe 2. Where the pushbutton is small enough to be fully covered by the fingertip, the full stroke the pushbutton body 3 is pushed down until the fingertip hits an upper edge of the pipe 2 is generally utilized to give a single switching action. To provide such a pushbutton device with two mechanical switching actions, the pushbutton device would require the pushbutton body to move in two successive strokes respectively for the two switching movements of the pushbutton device. With such an arrangement, the operator would have to depress the pushbutton body under varying the distance of stroke with the fingertip so as to effect the different switching actions independently. The pushbutton device would therefore need sustained attention to operate properly and be infeasible from a practical standpoint.
Various pushbutton devices have been proposed and used which include a click mechanism for moving a pushbutton in distinct stepped strokes. The prior click mechanisms however are complex in structure with the results that the pushbutton devices incorporating the click mechanisms are complicated in construction and large in size. When the pushbutton is depressed with a stronger force than normally expected, the click mechanism also tends to allow the pushbutton body to move all the way down through the two strokes beyond the intermediate position in which the pushbutton is to be stopped at the end of the first stroke.